A 'SEED-loxP-sfGFP' ('scarless editing by element deletion') cassette has been inserted into the endogenous ihog locus, at the C-terminal end of the coding region. The SEED-loxP-sfGFP sequence is composed of a loxP cassette containing a Disc\RFP^{DsRed(T1).3xP3.cHa} marker, with the loxP cassette flanked on the 5' side by 3 copies of the target site for the 'gRNA#1' guide RNA (sequence of this guide RNA is GTAGTACGATCATAACAACG) and on the 3' side by 3 copies of the target site for the 'gRNA#2' guide RNA (sequence of this guide RNA is GTACATCCATACAGTACCAG), and with the 5' and 3' parts of the split sfGFP sequence sharing a repeated sequence of ~400bp. If double-strand breaks are induced at both guide RNA target sites (by providing Cas9 and both of the 'gRNA#1' and 'gRNA#2' guide RNAs), single-strand annealing (SSA) repair can seamlessly remove the SEED-loxP-sfGFP cassette (including the Disc\RFP^{DsRed(T1).3xP3.cHa} marker) and reconstitute a functional sfGFP tag sequence.